Abstract: A method for manufacturing coils which achieves an uniform and complete curing of the paper impregnated with epoxy thermo curable resin placed between conductors by applying an electric current uniformly to all portions of the coil thus completely heating the coil, including the conductors near the core.

Abstract: A porcelain bushing for transformers withstanding impulse voltages rated at 45 kV and 1.2/50 &mgr;s without external flashover, having a creepage to arcing distance ratio of 1.05 to 1.24. The bushing includes a body constituted by a flange fitted with a gasket seat groove, a neck having a curvature radius ranging from 5 to 7 mm, and a mouth equipped with a two-level stepped gasket seat and a semicircular groove. A threaded shank for the attachment of the porcelain bushing to the mounting surface and a groove rail extending along the shank's thread is also provided. In a preferred embodiment, the body is coated with glassy enamel in order to protect the porcelain material against contamination by external agents as well as against the adoption of water.

Abstract: A method for manufacturing coils which achieves an uniform and complete curing of the paper impregnated with epoxy thermo curable resin placed between conductors by applying an electric current uniformly to all portions of the coil thus completely heating the coil, including the conductors near the core.